1. Field of the Invention
The present invention relates to a method and apparatus for multimedia broadcast and multicast service (MBMS) counting in a multimedia broadcast and multicast service single frequency network (MBSFN).
2. Description of the Related Art
A long term evolution-advanced (LTE-advanced) system standard defines a multimedia broadcast and multicast service single frequency network (MBSFN) to provide a broadcasting service through a communication network.
The MBSFN refers to a technology that simultaneously transmits the same data, at the same time, by synchronizing radio resources in all E-UTRAN NodeBs (eNBs) included in an MBSFN area. A signal from a neighboring eNB may be a gain to a user equipment (UE), as opposed to being interference, when the MBSFN technology is utilized.
Therefore, in the MBSFN area, the UE may recognize MBMS data transmitted from all eNBs as MBMS data transmitted from a single eNB. In the MBSFN area, although the UE moves, a broadcasting service may be continuously provided without an additional handover process.
An MBSFN-based MBMS service may provide a broadcast and multicast service.
The broadcast service may refer to a service provided over a network, unilaterally. When the broadcast service is provided, the UE may selectively receive a service irrespective of a connection state of a radio resource control (RRC). Therefore, a number of UEs receiving services from a particular eNB may be difficult to be recognized, currently, in a network.
Also, to receive a multicast service, the UE may need to join a multicast service group while the UE is in a radio resource control (RRC)-connected state. Therefore, at the time when the UE joins the multicast service group, counting information associated with a corresponding service may be recognized. However, when the UE moves to a new cell while in an RRC-idle state, it is difficult to maintain the counting information associated with a corresponding eNB, accurately.
When MBMS counting is not accurately performed with respect to the MBMS service, the eNB may continuously provide a service that the UE does not actually receive. Therefore, wireless resources may be wasted.
A wideband code division multiple access (WCDMA) system may solve the drawback by transmitting an MBMS access information message. That is, the WCDMA system may transmit an MBMS access information message to be used for MBMS counting in addition to an MBMS traffic information message, for a single-cell-based MBMS service as opposed to for the MBSFN-based MBMS service. The MBMS access information message may be transmitted via an MBMS control channel (MCCH).
When the MBMS counting is performed based on the MBMS access information, the UE may provide a response within a predetermined time. Therefore, a network load may increase, and performing the MBMS counting may in real time be difficult.
As described in the foregoing, the MBMS counting may not be applicable to the MBSFN-based MBMS service.
Therefore, there is a desire for a method that minimizes a waste of wireless resources by providing accurate MBMS counting information to a network, irrespective of the RRC connection state of the UE and a movement of the UE to a new cell when the MBSFN-based MBMS service is provided in the LTE-advanced system.